This project currently encompasses four areas of investigation based on several different samples with a total of approximately 200 families as participants. All studies were conducted with middle class families and first-born infants. The focal period of the research is from early infancy through the first two and a half years of life. Procedures vary with each sample, but include observations of mother-infant and father-infant interaction in the natural home environment, structured interactions in the laboratory, interviews, and questionnaires. The first area of inquiry concerns the effects of maternal work force participation on the child's early experiences. Three studies were performed with employed and homemaker mothers, one involving time-sampling observations of mothers and fathers with their infant in the home, a second involving continuous behavioral records of mother-infant interaction both prior to and after mother resumed employment, and the third involved structured laboratory observation of mother-toddler play. A second area of inquiry focused on normally occurring mother-infant separation experiences. A number of psychological dimensions were found to distinguish different types of separations, indicating that there exists considerable heterogeneity subsumed under the concept of "separation." Different psychological consequences were found with regard to security of attachment, distress in separation situations, and reactions to unfamiliar adults in separation contexts depending upon variation in past separation experiences. A third area of inquiry is concerned with the father's role in the family, both in "traditional" (single-earner) families and in families where both parents are employed. Distinctive aspects of father-infant interaction were identified for fathers who had more extensive experience on a one-to-one basis with their babies. The fourth area of inquiry concerns 3-person interactions, the mutual regulation of visual, vocal, proximity, and contact behavior of mothers, fathers, and infants depending upon the parents' psychological accessibility to the child and their degree of verbal engagement with one another.